RAID systems are storage systems, which allow for disk drive failures without a loss of data by implementing RAID algorithms in controlling a reading and writing of data and parity/redundancy to hard disk drives (“HDD”), which may require additional HDD for redundantly storing data and parity. The additional HDD however can add significantly to the overall cost of RAID systems. Particularly, in the case of a multiple mirroring solution for increasing storage robustness of the RAID system, such as, for example, a double mirroring solution involving two (2) additional HDDs redundantly storing data and parity for each HDD. The computer industry is therefore continually striving to maximize storage robustness of RAID systems while minimizing the cost of RAID systems.
Low cost HDD's that are derived from desktop (ATA-based) class HDD families are increasingly being used in Enterprise/server class applications to achieve much lower costs of storage. However, this comes at the expense of performance and reliability. To date, their usage has been typically restricted by applications or usage recommendations to workloads typified by lower duty cycles and lower I/O rates. It is desirable to intermix enterprise/server and desktop technologies without degrading performance and reliability of the systems.